That rumor comes courtesy of Radar Online, which claims the couple, who are also parents to button-cute 21-month-old daughter Harlow, got a marriage license last week and said "I do" in a "top secret ceremony" on Wednesday.

Nicole's rep didn't respond to our request for comment on the knot-tying rumblings, but an insider tells Radar that the former party girl-turned-hands-on mom has been "talking more seriously" about making things legal since the August death of her onetime fiancé, Adam "DJ AM" Goldstein.

Adding to the speculation: TMZ reports Sparrow's birth certificate only contains the name "Madden," not "Richie Madden," like Harlow's.